Previously unreleased CCTV footage has been screened in York as part of the investigation into the disappearance of Claudia Lawrence.
The footage shows two people seen near her home at what police said was a "potentially significant" time.
The 35-year-old chef, who lived in the Heworth area of York, was last seen on 18 March 2009.
The detective in charge of the investigation said he was actively pursuing "new leads".
In February, police undertook a fresh search of the alleyway behind Miss Lawrence's home and officers said the CCTV footage was linked to that.
Det Supt Dai Malyn, head of North Yorkshire Police's Major Crime Unit, said two people had been captured on camera at 19:15 GMT on 18 March.
Miss Lawrence had phoned her parents around that time but has not been seen since.
"Of particular interest to the investigation team is the person who is seen walking down Heworth Place which leads to the back of Claudia's house," he said.
"The person goes out of camera shot but reappears just over a minute later. They appear to be carrying a bag over their shoulder.
"As the person heads back towards Heworth Road they suddenly stop when another unknown person walks past."
The review of the case, which began in 2013, led to two arrests but no-one has been charged in connection with the case.
Det Supt Malyn said: "In the coming weeks and months we may make additional arrests as we continue to develop our lines of enquiry."
He said that the force might not be able to prove what had happened to Miss Lawrence.
"But that will not be for lack of determination, tenacity and meticulous detective work, nor whilst there are still clues that need to be investigated," he said.